The present invention relates to a shut-off valve for a vacuum hose connected to a hand tool. More particularly, the present invention relates to an automatic shut-off valve for an air-driven hand tool wherein the exhaust air from the hand tool opens the valve controlling the vacuum airflow applied to the tool.
It is known in the art to include a vacuum or other collection device to remove debris and dust produced by a tool. In particular, a vacuum source may be affixed or attached to a tool to draw off the dust from a sanding operation while the tool is in use. Generally, the vacuum being pulled on the hand tool is continuous regardless of whether the tool is in use or not. When the tool is not in use, the air being drawn through the vacuum line is pulled through the tool creating a great deal of noise.
It is also known in the art to have a valve system that may direct the vacuum to a particular tool being used. However, generally this requires a second control unit to ensure that the valve is directing the vacuum airflow to the proper tool. Furthermore, this system does not include an automatic shut-off such that a valve associated with a given tool is only opened when the tool is powered on for use, and is automatically closed when the tool is powered off.
It is also known in the art to have an automatic activation for a vacuum when a particular tool is activated. Generally this is performed with electronic switches that sense when the tool is actuated and then turns on a vacuum system. Therefore, the vacuum is not applied when the tool is not in use. Additional circuitry and switches are also required to operate such a system to ensure that the vacuum airflow is started only when the tool is in use.
It would therefore be desirable to provide a system where a vacuum airflow is pulled through a tool only when the tool is in operation.
It would further be desirable to provide a valve that can be affixed to any air-driven tool, that can also be attached to a vacuum line to thus control the application of a vacuum airflow to the tool.
It would also be desirable to provide a valve that may be placed anywhere in a vacuum line lending to a tool. It would also be desirable to provide such a valve that may be retrofitted to existing tools and vacuum lines.
Finally, it would be desirable to provide a system in which a continuous vacuum airflow may be drawn through a vacuum line coupled to a tool without drawing the vacuum airflow through the tool itself. The vacuum airflow would ideally only be drawn through the tool when the tool is activated, and thus activation of the tool itself would control opening of the vacuum line valve.
The above mechanism and other features are provided for by a vacuum shut-off valve in accordance with the preferred embodiments of the present invention. The vacuum shut-off valve includes a first section and a second section of hose interconnected in flow communication with one another. Placed in a first section of hose, which is coupled to an exhaust port of an air-driven tool, is a first valve. The first valve preferably comprises a ram valve or a slideable valve. Positioned in the second section of hose which is coupled between a vacuum port of an air-driven tool and a vacuum source is a second valve. The second valve preferably comprises a butterfly valve.
When the air-driven tool is activated, air travels through the tool and is exhausted out of the exhaust port. When the air is exhausted from the exhaust port, the first valve is moved from a first position to a second position. The first valve is interconnected to the second valve thereby operating the second valve when the first valve is moved. The second valve is in a closed position until the first valve is moved to the second position, where upon the second valve is opened. When the second valve is opened, the vacuum airflow from the vacuum source is pulled through the tool through the vacuum port, thus removing dust and debris created by the tool through the second section of hose.
The first valve is only moved to the second position when air is exhausted from the air-driven tool; therefore the first valve is only moved when the air tool is being operated. Due to this arrangement, the second valve is also only moved to the open position when the air tool is being operated, therefore selectively allowing a vacuum airflow to be applied to the tool only when the tool is being operated. The vacuum airflow is not allowed to be pulled through the tool when the second valve is in the closed position. Thus, an automatic vacuum airflow shut-off system is created such that the vacuum airflow is only pulled through the tool when the tool is being operated.